I'm reading this from my Blackberry so its hard to see the sample clearly, but it looks like the leading edge in the center is extra weak then offsetting onto the trailing edge - if that's the case the fuser needs a PM.
Damp paper is also famous for faded images in high humidity areas like mine - try a fresh sealed ream.
The general image looks more like PTR clutch or maybe PTR bias. If you just WD40'd the clutch that's gonna be the problem. I don't replace them anymore unless the hubs are totally shot because the new ones used to need the same disassembly / clean the dried grease / lube with a good grease / reassemble treatment that you had to do on an old one.
The line speed difference in thick modes is enough to cause a stiff clutch to fail, but eventually it would show up on normal paper.
Bookmarks